Question 705 of 981
AZ-900 Describe cloud concepts Practice Question
Which cloud concept refers to the ability to recover quickly from a failure without impacting user experience?
⚠ Common exam trap
Test-takers frequently confuse reliability with scalability, thinking that scaling out resources automatically ensures recovery, but reliability specifically requires redundant infrastructure and automated failover, not just resource elasticity.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Reliability
Reliability is the cloud concept that ensures a system can recover quickly from failures, such as hardware crashes or network outages, without noticeable impact on end users. This is achieved through redundancy, fault tolerance, and automated failover mechanisms, which maintain service continuity and uptime as defined in SLAs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Scalability
Why it's wrong here
Scalability is the ability to adjust resource capacity either horizontally (adding/removing instances) or vertically (increasing/decreasing VM size) in response to current demand. It handles growth or contraction in load, not the recovery of operations after a failure event. A workload can be highly scalable yet still lack redundancy or failover mechanisms, so scalability does not satisfy the requirement to sustain operations through failures.
- ✓
Reliability
Why this is correct
Reliability is the Azure Well-Architected Framework pillar that enables systems to recover from failures and continue functioning while meeting defined availability targets. It includes concrete design techniques such as deploying across availability zones, using fault domains, implementing load balancing, and configuring backup/Disaster Recovery strategies to achieve specific RTO (Recovery Time Objective) and RPO (Recovery Point Objective) metrics. Because the scenario explicitly asks about recovering from failures and sustaining operations, this is the correct answer.
- ✗
Agility
Why it's wrong here
Agility in Azure refers to the speed at which you can provision, configure, and deallocate resources through self-service portals, Infrastructure-as-Code templates, and automation. It emphasizes time-to-market and the ability to experiment quickly, not operational continuity under failure conditions. While agility can help you rebuild assets fast, the pillar that governs designing for fault tolerance, redundancy, and defined recovery targets is reliability, not agility.
- ✗
Cost efficiency
Why it's wrong here
Cost efficiency is the cloud pillar focused on financial optimization: rightsizing resources, using reserved instances or Azure Hybrid Benefit, and applying Azure Cost Management to monitor spend. It measures and reduces the amount of money spent on cloud workloads, but it has no relation to operational recovery from infrastructure failures. Choosing cost efficiency would incorrectly equate saving money with maintaining continuity of service.
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Last reviewed: Jun 11, 2026
This AZ-900 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the AZ-900 exam.
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